1. Field of the Invention
The present invention generally relates to a transfer device and, more particularly, to a magnetic transfer device well suited for the handling of a minute electronic component part.
2. Discussion of the Related Art
Semiconductor laser devices are generally formed by dicing a laser bar into individual laser elements. The quality of the individual laser elements is dependent upon the integrity of the facet sides of the laser bar being diced. In general, laser bars are cleaved from a laser cell. An example of a material used in the manufacture of laser devices is GaAs. GaAs, which has a cuboidal crystal structure, is very brittle however. Thus, cleaving of GaAs laser bars is a key factor in the manufacture of GaAs laser devices.
An apparatus for producing high quality laser bars is a jaw cleaving device disclosed in commonly assigned U.S. Pat. No. 5,154,333. With reference now to FIG. 1, the jaw cleaving device (not shown) cleaves a laser bar 10 from a cell 12 according to the following. To begin, the cell 12 is mounted in the cleaving device. A first jaw 14 is then applied to a margin area 16 at one end of the laser bar 10 from which a cleavage 18 is to be propagated. A second jaw 20 is applied to a margin area 22 at an opposite end of the laser bar 10, the second jaw 20 further being provided with a weight 24 used as a biasing force to ensure separation of the laser bar 10 from the cell 12 along the same crystallographic plane 26. The cleaving device exerts a rotational force R upon the cell 12 to effectuate the cleaving of laser bar 10. Upon separation of the laser bar 10 from the cell 12, the laser bar 10 is ready for further processing. The laser bar 10 thus produced is of high quality and has facet sides 28 of high integrity.
The integrity of the facet sides 28 of the laser bar 10 must be maintained to avoid defects in subsequently formed laser devices. Defects in the facet side of a laser device, which can include a chipped or shingled surface, cause undesired dispersement of light by reflections, thereby lowering a total amount of useful light emanating from the laser. In addition, reflected light at a shingled surface causes heat generation which can lead to catastrophic optical damage. That is, portions of the laser's facet surface can break off due to heat damage. The integrity of the facet sides of the laser bar is thus very important in order to subsequently produce a high quality laser device free of defects.
In addition to producing cleaved laser bars having high quality facet sides, it is highly desirable to perform the cleaving in an ultra-high vacuum (UHV) environment, and more particularly, a UHV environment free of O.sub.2 and H.sub.2 O. Exposure of the optical facet surfaces of the laser bar to O.sub.2 and H.sub.2 O results in the formation of an oxide layer upon the surfaces. Such an oxide layer absorbs light energy and causes diffusion of light. As discussed above, absorption of the light energy may result in catastrophic optical damage to the resultant laser device.
Subsequent to being cleaved, the laser bars are required to be transferred from the cleaving device to a carrier fixture in preparation for further processing. In view of the foregoing, the cleaved laser bars must be critically handled. In addition, due to the geometry of the laser bar and the UHV environment, the transferring of the laser bar becomes a critical step in the manufacturing of laser devices. In this regard, physical clamping devices are undesirable since any stresses exerted by the handling device would be detrimental to the integrity of the laser bar facet sides. The geometry of the cleaved laser bars are small in size, which can be on the order of 150 .mu.m H.times.750 .mu.m W.times.13.5.times.10.sup.3 .mu.m D or of other minute dimensions as required to provide a desired wavelength of light from individual laser devices, and thus not well suited for being handled by a physical clamping device. In addition, the handling device should be capable of operating under a UHV environment. Prior techniques for handling laser bars, including the use of adhesives and vacuum hold tools, are unsuitable for use in the UHV environment. Specifically, a disadvantage of adhesives or the like is that they outgas under UHV pressure and would cause contamination of the laser bar surfaces. Likewise, vacuum suction tools could not be employed, since the vacuum suction tools would not have any suction pressure in the UHV environment.
There is thus needed a device which can critically handle cleaved laser bars and which is capable of operating in a UHV environment.